1. Field of the Invention
Arrangement with at least one superconductive cable which is arranged in a cryostat serving for conducting a cooling agent, wherein the cryostat includes at least one thermally insulated metal pipe, wherein an electrically well insulated material is arranged on the outside on the cryostat, wherein the electrically well insulated material contacts the cryostat (EP2 071 589 A1).
2. Description of Related Art
A superconductive cable has at least one conductor of a special material which, at sufficiently low temperatures, changes over into the superconductive state. The direct current resistance of the conductor then equals 0. Suitable materials are, for example, YPCO (yttrium-barium-copper oxide) or BISCCO (bismuth-strontium-calcium-copper oxide). At sufficiently low temperatures for such a material are, for example, between 4 K and 110 K for reaching the superconductive state. Suitable cooling agents are, for example, nitrogen, helium, neon and hydrogen or mixtures of these materials, each in the gaseous or liquid state. Superconductive cables with cold dielectric and hot dielectric are known.
In a superconductive cable with cold dielectric, the superconductive conductor is surrounded by a dielectric consisting of layers of insulating material, wherein a liquid cooling agent is present as an impregnating agent in the dielectric (insulation). Such a cable is composed, for example, of the conductor as internal conductor and a screen or return conductor which is arranged concentrically which are separated from each other and kept at a distance from each other by the dielectric. An appropriate cable of this type is surrounded by a cryostat which conducts a cooling agent, wherein the cryostat consists of, for example, two concentrically arranged metal pipes which are insulated relative to each other by a thermal insulation.
Superconductive cables with hot dielectric include a conductor which is arranged directly in a cryostat conducting the cooling agent. In this case, dielectric and screen or return conductor are arranged outside of the cryostat while contacting the latter.
In all known arrangements with superconductive cables, no matter whether with cold or hot dielectric, the electrical conductors must be dimensioned in such a way that the energy input in the case of a short circuit does not lead to the destruction of the cable and/or to undo heating of the cable. This requires a sufficiently large electrically conductive cross-section of the conductor with appropriately large dimensions of the respective arrangement. In addition, there is the fact that such an arrangement composed of cryostat and enclosed superconductive cable must be pulled into the cable for its operation. For this purpose, on the outside of the cryostat is attached a pulling mechanism through which the dimensions of the arrangement are further increased. Moreover, the inside width must be adapted to these relatively large dimensions.